Lubricating compositions having utility as engine oil formulations typically contain dispersants, detergents, antiwear agents and anti-foamants as well as other types of lubricants. Lubricating oil compositions of this type typically control sludge and varnish formation and, in general, promote good engine life. No one typical lubricating oil composition necessarily solves all the deleterious effects known to occur with an automotive engine.
A lubricating oil composition that performs adequately in one engine at given operating conditions does not necessarily perform adequately when used in a different engine or under different conditions. While theoretically, lubricants could be designed for each possible combination of engine and seivice condition, such a strategy would be unpracticable because many different types of engines exist and the engines are used under different conditions. Accordingly, lubricants that perform well in different types of engines and across a broad spectrum of conditions (e.g., fuel type, operating load and temperature) are desired. Design of lubricating oil compositions is further complicated in that the concentrated mixture of chemicals added to lubricating oil base stocks to import desirable properties should perform well over a broad range of different quality base stocks. Meeting these requirements has been extremely difficult because the formulations are complicated, tests to ascertain whether a lubricant performs well are extremely expensive and time consuming, and collecting field test data is difficult since variables cannot be sufficiently controlled.
U.S. Pat. No. 3,087,936 (LeSuer, Apr. 30, 1963) relates to a process for preparing oil-soluble nitrogen- and boron-containing compositions comprising treating an acylated nitrogen composition characterized by the presence within its structure of (A) a substantially hydrocarbon substituted succinic radical selected from the class consisting of succinoyl, succinimidoyl, and succinoyloxy radicals wherein the substantially hydrocarbon substituent contains at least 50 aliphatic carbon atoms and (B) a nitrogen-containing group characterized by a nitrogen atom attached directly to said succinic radical, with a boron oxide, boron halides, boron acids, and esters of bcoron acids in an amount to provide from about 0.1 atomic proportion of boron for each mole of said acylated nitrogen composition to about 10 atomic proportions of boron for each atomic proportion of nitrogen of said acylated nitrogen composition.
U.S. Pat. No. 4,741,848 (Koch et al., May 3, 1988) relates to a process which comprises reacting
(A) at least one hydroxy-substituted ester, amide, or imide of the formula ##STR1## wherein R is a divalent hydrocarbyl group, X is --OR' or --NR'R", wherein R' is a hydrocarbyl group and R" is hydrogen or a hydrocarbyl group, Y is OH or X, m is zero to 2, or X and one Y taken together represent a single NR' group forming a cyclic imide, and n is an integer from 1 to 10 provided that only one free hydroxyl group is attached per carbon atom of the hydrocarbyl group R, with PA1 (B) a boron compound selected from the group consisting of boric acid, boron trioxide, boron halides, boron amides and boron esters. PA1 (A) a borated nitrogen containing-dispersant with a total base number of from 20 to 160 on an oil-free basis; PA1 (B) a metal salt of a phosphorus acid; and PA1 (C) a metal overbased composition comprising at least one carboxylate, phenate, or sulfonate wherein the metal is lithium, sodium, potassium, magnesium or calcium, and wherein the improvement comprises PA1 (D) a borate ester. PA1 (1) Hydrocarban substituents, that is aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl or cycloalkenyl) substituents, aromatic, aliphatic- and alicyclic-substituted aromatic nuclei and the like, as well as cyclic substituents wherein a ring is completed through another portion of the molecule. PA1 (2) Substituted hydrocarbon substituents, that is, those containing non-hydrocarbon radicals which, in the context of this invention, do not alter the predominantly hydrocarbyl character of the substituent. Those skilled in the art will be aware of suitable radicals (e.g., hydroxy, halo, (especially chloro and fluoro), alkoxyl, mercapto, alkyl mercapto, nitro, nitroso, sulfoxy, etc., radicals). PA1 (3) Hetero sulstituents, that is, substituents which, while predominantly hydrocarbon in character within the context of this invention, contain atoms other than carbon present in a chain or ring otherwise composed of carbon atoms. Suitable hetero atoms will be apparent to those skilled in the art and include, for example, sulfur, oxygen and nitrogen and form substituents such as, e.g., pyridyl, furanyl, thiophenyl, imidazolyl, etc.
U.S. Pat. No. 4,859,353 (Colclough, Aug. 22, 1989) provides for sulfur containing borate esters of the formula ##STR2## (wherein each R is a hydrocarbyl group optionally substituted by one or more --XR" group, or the two R groups attached to one boron represent a group --(R'.sub.2 C).sub.m, x is from 1 to 4, each n is from 1 to 6, each m is from 2 to 4 and each R' is hydrogen, an --XR" group, or a hydrocarbyl radical optionally substituted by one or more --XR" group, X is O, S or NR" or two groups R' together form an alicyclic or heterocyclic ring, and R" is hydrogen, a hydrocarbyl radical or a hydrocarbyl-carbonyl group) and mixtures and polymeric forms thereof.
U.S. Pat. No. 5,078,893 (Ryer et al., Jan. 7, 1992) relates to a mutually compatible combination of additives and their use to impart antiwear, oxidation inhibition and friction modification to power transmission compositions, particularly automatic transmission fluids. The additives comprise an organic phosphite ester such as triphenyl phosphite and a hydroxyl amine compound, such as that having the formula ##STR3## preferably in combination with a dispersant such as a polyisobutenyl succinimide or a borated derivative thereof.
U.S. Pat. No. 5,334,329 (Vinci et al., Aug. 2, 1994) describes a lubricating composition which comprises a mixture of (A) a major amount of an oil of lubricating viscosity, (B) a dispersant effective amount of at least one ashless dispersant, and (C) a minor, effective amount of at least one demulsifier characterized by the formula ##STR4## wherein R is a hydrocarbyl group, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are each independently hydrogen or hydrocarbyl groups, and X is oxygen or NR' wherein R' is hydrogen or a hydrocarbyl group. In one embodiment, the dispersant (B) is a boron-containing composition.
U.S. Pat. No. 5,612,295 (Bell et al., Mar. 18, 1997) relates to multifunctional additive compositions formed by a process which comprises heating concurrently or in any sequence (a) an oil-soluble ashless dispersant containing basic nitrogen with (b) an alkoxylated alcohol of at least 8 carbon atoms and (c) a borating agent to a temperature in the range of about 50.degree. to about 150.degree. C., and if water and/or solids are present in the resultant mixture, removing both of them or whichever of them is present in the resultant mixture. These additives, once prepared and filtered, are clear mixtures that tend to remain free of haze and solids even after long periods of storage at elevated temperatures such as 70.degree. C., even though they may contain high levels of boron within the range of proportions described hereafter.
U.S. Pat. No. 5,698,498 (Luciani et al., Dec. 16, 1997) relates to a lubricating composition comprising a major amount of an oil of lubricating viscosity and (A) a minor amount of at least one hydroxyalkyl dithiocarbamate or at least one borate thereof wherein the dithiocarbamate is derived from an amine other than an alkyl or alkenyl succinimide. In another aspect, this reference relates to a lubricating composition comprising a major amount of an oil of lubricating viscosity, a hydroxyalkyl dithiocarbamate or a borate thereof, and (B) at least one sulftir compound or (C) at least one phosphorus or boron antiwear or extreme pressure agent. The lubricants and fluids have improved antiwear and extreme pressure properties including improved antiscuff protection.